Platform-scale



(No Model.)

0. BRUNNER.

PLATFORM SCALE.

No. 451,613. Patented May 5,1891.

UNITED STATES PATENT QFFICE.

CHARLES BRUNNER, or PERU, ILLINOIS.

PLATFORM-SCALE.

SPECIFICATION forming part of Letters Patent No. 451,613, dated May 5,1891.

Application filed $eptemher 13,1890. Serial No. 364.86% (N0 model.)

To will whom it may concern.-

Be it known that I, CHARLES BRUNNER, of Peru, in the county of La Salleand State of Illinois, have invented certain new and useful Improvementsin PlatfornrScales; and I do hereby declare that the following is afull, clear, and exact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

This invention relates to weighing-scales of the platform order, and hasfor its primary object to provide a construction by which the effects ofexpansion and contraction of the levers, resulting from changes intemperature, are obviated and greater accuracy attained.

It has for a secondary object to provide a construction for thesuspension of the oscillating platform-supporting cross -bars of thelever system whereby their poise is rendered more sensitive.

In the accompanying drawings, which illustrate my invention, Figure 1 isa top or plan view, the platform being broken away at one end. Fig. 2 isan elevation seen from that side of the apparatus at which thescale-beam is located, the View being obtained by a removal 'of the sidewall of the pit. Fig. Sisavertical transverse section in the line 3 3 ofFig. 2, looking in the direction indicated by the arrows applied to saidline.

A represents a plat-form having two longitudinal beams A A, which extendnearly the length of the pit B.

O C are oscillating bars for the support of the platform, beingsuspended across the ends of the pit from corner-irons D D. Thissuspension is effected by means of links 0 0, one at each end of eachbar 0, engaged with the corner-irons and with knife-edge bearingpins 0'passing through lugs 0 0 on the upper sides of the bars and through thelinks 0, as clearly shown in Fig. 3. Each cross -bar O is provided withtwo upwardly-projecting flanges C C, terminating in hardened knifeedgesextending lengthwise of the bar, butlecated out of the central line ofthe suspending-pins c on that side of the bar 0 toward the middlle ofthe scale or platform. Upon these projections C rest the beams A A ofthe platform, the latter being provided with suitable ironsorhardened-metalsurfaces at the points of contact with said projections0.

Each of the oscillating bars 0 is provided with a lever-arm, engaging,in the usual way, a stirrup E upon the lower end of the scalerod E, bywhich the scale-beam is operated; but said lever-arms, instead of beingcontinuous or severally integral, as ordinarily construeted, are madeeach in two parts which are so connected with each otheras to permit afree lengthwise movement of one with respect to the other,while at thesame time transmitting the power from the platform to the scale-rod.Such two parts of the lever-arms are shown clearly, in Figs. 2 and 3, tobe composed of short portions or arms 0 which are rigid with thecross-bars C and the extensionbars C engaged at their free ends with thestirrups E. As herein illustrated, the connection of the extension-barsO with the arms 0 by which the desired lengthwise movement abovereferred to is permitted, consists in arranging the bars 0 above thearms C giving sliding contact of the extremity of said bars C with thearms C and applying links F to knife-ed ge cross-pins f f between thepoint of contact of the bars 0 with the arms 0 and the connections ofsaid bars 0 with the scale-rod. By thus making the lever-arms in twoparts having the possibility of free longitudinal movement with respectto each other the effect of expansion and contraction, which has beenfound to materially disturb the accu *acy of the scale by elongating orshortening the integral lever-rods heretofore used, is obviated, and thescale is found to weigh with substantially uniform accuracy at varyingtemperatures.

Other modes of connecting the two parts of the several lever-arms O Cmay be obviously employed with the same effect, and I therefore do notwish to be restricted to the specific construction of the connectionherein illustrated.

I claim as my invention- 1. In a weighing-scale, the combinatiomwith theplatform and the scalerod, of the oscillating-bar O, supporting theplatform and provided with two part lever arms connecting with thescalerod, the parts of each of said lever-arms having a connection witheach other which permits free lengthwise movement of one part withrespect to the other, ings of the latter upon said arms 0 and theirwhereby expansion and contraction thereof connection with the draft-rodof the scale. are automatically compensated. In testimony that I claimthe foregoing as 2. In combination With the oscillating bars myinventionI aflix mysignatnre in presence 5 C, supporting the platform andprovided with of two witnesses.

armsC the bars C eonneetin 'with the drafti 3 r 1 rod of the scale andarranged to hear at their LRUA R opposite ends upon the arms 0 and linksWitnesses: connecting the arms 0 at their extremities ll. A. ZUBROD, rowith the bars 0 at points between the boar- .Tos. MOSBACK.

